Interact CardioVasc Thorac Surg 2006;5:454-455. doi:10.1510/icvts.2005.127381
© 2006 European Association of Cardio-Thoracic Surgery
Negative results - Cardiac general |
Non-anastomotic avulsion of a left internal mammary artery graft – a rare complication of minimally invasive direct coronary artery bypass surgery
Andrew P. Ashersona,*,
Hunaid A. Vohrab,
Mark J. Masona and
Jullien A. Gaerb
a Department of Cardiology, The Royal Brompton and Harefield Hospitals NHS Trust, Harefield Hospital, Hill End Road, Harefield, UB9 6JH, UK
b Department of Cardiothoracic Surgery, The Royal Brompton and Harefield Hospitals NHS Trust, Harefield Hospital, Hill End Road, Harefield, UB9 6JH, UK
Received 30 December 2005;
received in revised form 6 March 2006;
accepted 3 April 2006
*Corresponding author. Tel.: +44(0) 1895823737; fax: +44(0) 1895828962.
E-mail address: a.asherson{at}rbh.nthames.nhs.uk (A.P. Asherson).
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Abstract
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Objective: To describe a rare complication of minimally invasive coronary artery bypass surgery. Method: Case report. Results: We present a 72-year-old patient with a left anterior descending artery stenosis who underwent elective minimally invasive direct coronary artery bypass (MIDCAB) surgery. Three months post-operatively he developed an anterior chest wall haematoma with electrocardiographic and enzyme evidence of myocardial ischaemia, though without haemodynamic embarrassment. Surgical exploration revealed non-anastomotic avulsion of the LIMA graft, which was bleeding freely into the left hemithorax. Conclusions: Minimally invasive direct coronary artery bypass surgery is now widely practised. Post-operative interruption of the left internal mammary artery graft is uncommon and avulsion of the graft proximal to the anastomosis with the left anterior descending artery has only been described in the literature on three occasions. This complication has been reported once in the setting of conventional bypass surgery and twice in the setting of minimally invasive direct coronary artery bypass surgery. In all of these cases, abrupt graft failure resulted in significant haemodynamic and/or ischaemic compromise, and all occurred within two weeks of surgery. Clinicians should be reminded of this rare though potentially catastrophic complication of MIDCAB surgery.
Key Words: MIDCAB; LIMA; Complications
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1. Case report
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A 72-year-old man presented with a two-day history of swelling in the left pectoral region, three months after elective minimally invasive direct coronary artery bypass (MIDCAB) surgery. There was no history of fever, chest pain or recent trauma. Examination revealed a tense, non-pulsatile swelling above the well-healed surgical scar. A resting ECG revealed no new changes and markers of myocardial necrosis were negative. Ultrasound imaging revealed a 3x7 cm chest wall collection. The patient was admitted to hospital and commenced on antibiotics for presumed wound infection. Four days later the patient developed chest pain associated with anterior ECG changes and a troponin rise. As the swelling had also increased in size, the patient was referred to a specialist centre for further management.
Thoracic CT imaging revealed a 20 cm hypodense loculated collection sub-sternally with significant extra-thoracic extension (Fig. 1). Digital subtraction coronary angiography demonstrated interruption of the LIMA graft, which was blind ending into a false aneurysm (Fig. 2).
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Fig. 2. Digital subtraction angiographic image during selective injection into the left internal mammary artery – contrast pooling in false aneurysm.
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Exploratory surgery was performed through the original mini-thoracotomy though the incision was extended for the purpose of re-exploration. This revealed a large haematoma within the left hemithorax. The LIMA had avulsed 2 cm proximal to the anastomosis with the LAD and was bleeding freely. The distal segment was occluded. Haemostasis was ensured with Ligaclips to both proximal and distal segments. No further LAD bypass was carried out. The post-operative course was unremarkable. Six weeks post-operatively the patient had resumed normal activities and was free of angina.
Non-anastomotic avulsion of a LIMA graft as a complication of MIDCAB surgery has only been reported on two occasions [1,2]. A single report following conventional CABG is also described in the literature [3]. Unlike our patient, all cases already described presented early and with significant haemodynamic embarrassment.
The mechanisms for avulsion of an internal mammary graft remote from the site of anastomosis are unclear, though it would appear that sudden shear forces in vulnerable conduits might result in acute vessel transection. Central to the primary pathogenesis is undue tension on an arterial conduit still tethered to the chest wall, emphasising the importance of mobilising a sufficiently long arterial conduit in both MIDCAB and conventional bypass surgery. It is further hypothesised that localised intimal dissection at the site of ligated side branches may result in points of weakness in the conduit. As physical exertion has been implicated in two of the reported cases, a forceful Valsalva manoeuvre or abrupt respiratory excursion, with disruption of the LIMA at the sharp edge of the pericardium, have further been postulated as precipitants of avulsion in what may be assumed are vulnerable conduits.
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References
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- McMahon J, Bergsland J, Arani DT, Salerno TA. Avulsion of the left Internal mammary artery after minimally invasive coronary bypass. Ann Thorac Surg 1997; 63:843–845.[Abstract/Free Full Text]
- Radermecker MA, Grenade T, Desiron Q, Limet R. Avulsion of the left internal mammary artery graft after minimally invasive coronary surgery. Ann Thorac Surg 2001; 71:1401–1402.[Free Full Text]
- Morritt DG, Shah SS, Morritt AN, Kaul P. Acute transection of the left internal mammary artery remote from the anastomosis following coronary artery bypass surgery. Interact Cardiovasc Thorac Surg doi:10.1016/j.icvts.2004.08.001.
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Abstract
1. Case report